• John Reynolds (1989-1993)
Ms O'Connor and Mr Reynolds have a son, Jake (24). She remains on good terms with Mr Reynolds, who is based in London and has been involved with tracks for her new album 'How About I Be Me And You Be You', to be released on February 20. l Nick Sommerlad (2002-2003)
Ms O'Connor's second marriage was to journalist Nick Sommerlad, who she met at a concert. After a whirlwind romance, the couple tied the knot in 2002 but split less than two years later.
Distraught about the break-up, the singer vowed she would never marry again.
• Steve Cooney (2010-2011)
Her third marriage was to musician Steve Cooney in July 2010.
The Australian first met Ms O'Connor when she sang backing vocals for the group In Tua Nua in the 1980s, but it was decades later before they began a relationship, when Mr Cooney began playing guitar in her backing band.
A former member of the band Stockton's Wing, the respected musician was also half of the duo Cooney & Begley with the Co Kerry accordion player Seamus Begley.
Ms O'Connor later revealed in the Irish Independent that the marriage had ended in March after just eight months.
The singer has four children: a son, Jake Reynolds, by her first husband; a daughter, Brigidine Roisine Waters, born in early 1996, by columnist John Waters; another son, Shane, born on March 6, 2004, whose father is Irish folk musician and record producer Donal Lunny; and her fourth child, Yeshua Francis Neil, born in December 2006, whose father is her former partner Frank Bonadio.